Experimental Design: It can be a Crabshoot

Hello again, readers! June is over, and summer is starting in earnest! This marks the end of the second week in the REU program here at OIMB. This week was filled primarily with deciding on and designing our projects for the rest of the term. There are so many ways to approach the subject of trophic ecology; essentially the “who-eats-who” of an ecosystem. One of the common questions is: how do energy and nutrients get from the place where they enter the ecosystem all the way up to the higher levels of the food web? In terrestrial ecosystems, the trend can be a bit more straightforward; plants capture sunlight, and use carbon dioxide gas and water to produce sugars and other molecules which they use to build their bodies. Primary consumers (herbivores) such as bugs, deer, birds, or other herbivorous animals eat those plants, and are then eaten by secondary consumers, and so on up the food web. In marine ecosystems, this pattern tends to vary somewhat, though follows the same general pattern. In coastal ecosystems, energy enters as sunlight and is captured primarily by algae and photosynthetic plankton. How this energy gets distributed may follow a similar pattern as mentioned before, though can become a bit more convoluted. Many types of marine animals eat algae, but also eat each other; there tend to be a lot of opportunistic behaviors, especially when the presence of algae or other primary production is low. Some animals, such as the purple sea urchin Strongylocentrotus purpuratus, consume algae but tend to be “messy eaters” meaning they shred the food particles into small pieces, which are much more accessible to small animals such as snails or developing crabs. Their waste might also be enriched in nutrients such as nitrogen or phosphorous. Thus, the waste from urchins (primarily their poop), and perhaps even the algae itself, might be an important food source for young crabs, providing some of the essentials needed for growth in their juvenile stages until they are large enough to eat other things. I plan to study how different diets- such as different types of meat, algae, and sea urchin waste- affect growth rates in juvenile Dungeness crabs (Cancer magister).

This week we also attended a seminar on the synthesis of art and science, exploring topics such as science communication, biological illustration, and the ways that science inspires art, and vice versa. The week also included a LOT of tidepools; searching for and collecting some specimens for projects, learning about the ways that the structure and location of tidepools influence what is there, and just exploring the beautiful places the Oregon coast has to offer, such as the Cape Arago Lighthouse (below), Sunset Bay, and Bastendorff Beach. Several students were able to find an octopus, though I wasn’t there for that (sad day).

​ Now, at the end of the week, I’m preparing to begin the six-week experiment collecting data on Dungeness crab growth. The question has become: how do I fit 75 crabs in containers in a small water table while making sure they all have adequate water flow, oxygen, and space, without any cross-contamination? More on that to come.

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About me

Hey, readers! My name is Zade Clark-Henry. I'm from Salem, Oregon, and I'm an undergraduate student majoring in Natural Resources at Oregon State University, with an emphasis ecological studies, specifically forest ecosystems and ecological restoration. I'm interested in all types of science, but especially life sciences, and within that I'm most interested in ecological interactions between organisms. My non-academic interests include playing music, hiking, camping, exploring, kayaking, reading, and drinking tasty espresso.I heard about the Research Experience for Undergraduates (REU) program at the Oregon Institute of Marine Biology (OIMB) from a biology professor of mine at Chemeketa Community College in Salem; the program opened for applications in late February, and I applied as soon as I could. It was a very unique opportunity for me to engage in real research in the field with professionals, while also learning about marine biology, gaining professional development skills, and making connections with researchers in the field of marine biology, including fellow students from other universities around the country.OIMB is located in Charleston, Oregon, on the coast near the southern end of the state. It is a research and learning facility owned and operated by the University of Oregon, and hosts a number of specialists in marine biology, and is equipped with several labs, each with a unique area of expertise. The lab I've been assigned to is the Galloway Lab, known as the Coastal Trophic Ecology Lab (CTELab). It is run by Professor Aaron Galloway, who specializes in marine and freshwater ecology. His lab includes Julie Schram, a post-doc researcher; Reyn Yoshioka, his PhD student; and Zofia Knorek, a Master's student, each of whom are conducting their own research projects. My fellow REU partner in the CTELab is Leela Dixit, who is pursuing a degree in marine ecology.There are so many exciting possibilities within the field of marine ecology, and after some exploration (and asking a lot of questions), I narrowed my potential project down to looking at how various diets in Dungeness crabs (Cancer magister) affect their growth in young individuals. Interestingly, sea urchins eat various types of seaweed, and when they process it in their stomachs, they enrich the nutritional quality of the food they eat, and they spit back out a nutrient dense pellet that can be eaten by other organisms. I want to see if those pellets can sustain Dungeness crabs, and if they will promote growth. The other option I'm interested in is seeing what kinds of beach-dwelling organisms are supported by piles of seaweed that wash up on the beach (called "beach wrack"), and if different types of algae harbor different species, and how much life each can support before decomposing.

I’m looking forward to beginning my project and seeing where the rest of the summer takes me. Thanks for reading!